feat: add kotlin.indexing.enabled option

Author: weirongxu

package.json

@@ -95,6 +95,11 @@
           "default": 250,
           "description": "[DEBUG] Specifies the debounce time limit. Lower to increase responsiveness at the cost of possibile stability issues."
         },
+        "kotlin.indexing.enabled": {
+          "type": "boolean",
+          "default": true,
+          "description": "Whether global symbols in the project should be indexed automatically in the background. This enables e.g. code completion for unimported classes and functions."
+        },
         "kotlin.completion.snippets.enabled": {
           "type": "boolean",
           "default": true,